The present invention relates to material removing tools in general, and more particularly to improvements in rotary cutters of the type disclosed, for example, in U.S. Pat. No. 4,244,626 granted Jan. 13, 1981 to Klaus Konieczny et al. Cutters of the type to which the present invention pertains can be used with advantage in so-called advance working machines or moles wherein a boom carries one or more rotary cutters serving to penetrate into the material of a mine face and to remove therefrom rock, ore and/or other solid materials. Still more particularly, the invention relates to rotary cutters of the type wherein a rotor is driven by a shaft and carries a plurality of external material removing bits as well as a plurality of external nozzles serving to direct sprays of a fluid medium (normally water) against the mine face and/or against the bits.
The purpose of nozzles is to reduce the generation of dust, to cool the bits, and to extinguish sparks which develop as a result of penetration of bits into the material along the mine face. Presently known rotors of such cutters are provided with internal compartments which deliver the fluid medium to the orifices of the nozzles.
It was further proposed to use sprays of highly pressurized water as a means for removing comminuted material from the region where the bits penetrate into the mine face. To this end, the pressure of water must be raised to several hundred bars. However, it was found that such elevated pressures in the regions of the nozzles can be achieved only at an extremely high cost as well as that the presently achievable pressures do not invariably suffice to ensure satisfactory removal of comminuted or fragmentized material from the regions of the bits.